Mean Arms Exomag 9mm Luger 20 Round With Ejector Black

The Mean Arms Exomag 9mm Luger 20-round magazine with ejector is built for AR-15 shooters who want to run 9mm without swapping lowers or fussing with adapters. Drop this STANAG-profile magazine into your standard 5.56 lower, pair it with a 9mm upper (Glock or Colt variant BCG), and you're ready to shoot—no tools, no modifications, no magwell gymnastics. The ejector version works with standard blowback bolts, making it the straightforward choice for most 9mm AR builds.

What makes the Exomag stand out is its no-compromise design. You keep the same muscle memory as your 5.56 platform: identical magazine shape, same draw from your existing pouches, same reload feel. Training transitions seamlessly between calibers because you're literally using the same magazine body. The mag runs everything—standard rounds, hollow points, whatever you've got in the ammo can—and includes last-round bolt-hold open, because an AR should function like an AR.

Built from specially formulated polymer and coming fully assembled, the Exomag eliminates the trial-and-error some shooters hit with single-stack 9mm conversions. If you're building a dedicated 9mm upper or adding caliber flexibility to an existing lower, this magazine handles the job without reinventing your platform. Just confirm your BCG type before ordering—the ejector version pairs with standard blowback systems; ejectorless variants exist for Bearing Delay and CMMG Radial Delay uppers.

Key Features

• STANAG-profile design fits standard AR-15 magazines pouches and accessories
• No lower receiver modifications required—works with your current 5.56 lower
• Fully assembled; no tools needed to get running
• Last-round bolt-hold open for proper AR-15 operation
• Ejector compatible with standard blowback 9mm bolts
• Feeds all 9mm ammunition types, including hollow points
• 20-round capacity in black polymer

Specifications

Frequently Asked Questions

Will the Exomag work with my standard AR-15 lower?

Yes. The Exomag is designed to function with a standard 5.56x45 lower receiver without any modifications. You only need to swap in a 9mm upper with a compatible Glock or Colt variant BCG.

Do I need a magwell adapter or special magazine well to use this?

No. The Exomag has a STANAG outer profile and works directly in your existing lower receiver. No adapters, drilling, or additional hardware required.

What BCG types is the ejector version compatible with?

This ejector version is designed for standard blowback 9mm bolts. If you own a Bearing Delay upper or CMMG Radial Delay system, you'll need the ejectorless variant instead.

Can I use my existing 5.56 magazine pouches with this 9mm magazine?

Yes. Because the Exomag maintains the STANAG magazine profile, it fits standard AR-15 pouches, storage racks, and other accessories you already own, so you don't need to rebuy gear.